The present invention relates to the safety of airport runways.
More particularly, the invention provides a side barrier preventing foreign object debris (FOD) from entering a runway and taxiway and endangering aircraft.
The importance of keeping airport runways and taxiways clear of FOD is well known.
An important consideration requiring attention is that the large diameter engines used by jet aircrafts are most often located under the aircraft wings, thus bringing the engine intake perilously close to ground level. As aircraft jet engines can be severely damaged on ingestion of even small solid particles, a clean runway is needed to ensure the safe operation of the engines, particularly during take-off.
The arrival of FOD on a runway or taxiway is often due to winds or wind caused by jet blast which collect FOD from an outside area. After the wind abates and before any airplane is cleared for take-off a clean-up crew may be sent to clear the runway for both incoming and outgoing aircraft. The resultant delays can have a ripple effect on other flights resulting in angry passengers and much fuel wastage as incoming aircraft circle the airport in a holding pattern.
While it may appear at first glance that the erection of a FOD barrier on each side of a runway is a simple matter, it must be realized that under various circumstances (pilot error, fog, under carriage malfunction, a collision avoidance maneuver etc.) an aircraft may fail to adhere to the line marking the runway center and collide with the FOD barrier. If the barrier is rigid such a collision is likely to result in loss of life, injuries and a wrecked aircraft.
Accordingly Prevost in US Patent application 2008/0175665, and U.S. Pat. Nos. 7,207,742 7,223,047 and 7,677,833 discloses an arrangement wherein a downward slope is created adjacent to each side of the runway. A water impermeable material covers the slope, at the bottom of which a line of artificial grass is to collect FOD driven by jet blasts and water run-off from the runway. The drawbacks of this system include the difficulty of cleaning the artificial grass and the high cost of creating two or 3 levels where only one level—the surface of the runway—exists presently.